This invention relates to a temperature responsive control device that sequentially controls functions by sequentially actuated fluid flow valve and electrical switching means in the device.
Vehicle engines, particularly truck engines, are highly sensitive to internal temperature conditions for optimum operational characteristics and exposure to potential overheating damage. Consequently, temperature responsive controls and alarms have been developed to regulate, monitor, and signal the driver relative to engine temperature conditions. Illustrative units are set forth in U.S. Pat. Nos. Re. 26,840, 3,613,041 and 3,853,269. The control valves in U.S. Pat. Nos. Re. 26,840 and 3,853,269 typically operate shutters of the type for example in U.S. Pat. No. 3,198,298 or air operated fan drives that govern air flow through the radiator. See also U.S. Pat. No. 3,759,056. The unit in U.S. Pat. No. 3,613,041 electrically activates an electromagnetic fan drive or an alarm or shuts down the engine in the event of overheating. The control valves respond at a lower temperature than the alarm or shut down devices. Sometimes only one of these devices is used on an engine. However, both types can be employed on the same engine by providing two or three ports in the engine for insertion of a pair or more of temperature responsive elements into the coolant jacket. In this event, efforts are made to carefully preset these independently functioning devices to try to minimize interference therebetween.